Sam Strano

There is... and it's quite small. Take a pencil and lay it on your desk. Roll it slowly. Notice how much more the OD moves than the ID does? Bars work the same way. The inside of the bar adds very little resistance, and the further out you get from the center, the more leverage you have.

MyShibbyZ28

Just to elaborate further on what Sam said...

The outside of the bar is what gets most flex, and stress put on it because the outside has to move the furthest just simply because it is furthest from the center. The inside hardly moves. A good way to demonstrate it is to twist something. Yes, whatever you twist will move the same degree on the inside as the outside, but that is not what offers resistance. It has to do with leverage, and the further away from the center you get the more leverage you get. Now since the inside doesn't have nearly as much leverage, and can never have the same amount of leverage as the outside, you can take it out without much difference.

Bud M

I haven't weighed it, but my ST 35 mm bar is pretty damn heavy when you are laying on the floor holding it in place with one hand and trying to put in the bolts with the other. Quite a bit heavier than a 32 mm solid bar.
As far as disadvantages, the solid 35 is nice on flat pavement but makes the car kind of a handful on bad pavement. It's stiffer than I like for a daily driver.

43 percent actually

It doesn't. A hollow 35 mm bar with 6 mm walls would have a stiffness roughly equal to a 33.3 mm bar, assuming the same dimensions.
You can calculate the stiffness of a bar using the following formula (copied from a post on FRRAX): The stiffness of a straight bar is proportional to (D (Diameter) outside^4 - D inside^4). If the bar is solid, D inside=0, so that reduces to just D^4. None of the bars for a 4th gen are straight, so the numbers won't be exact, but they will get you in the ballpark.

ChrisUlrich

I am making the plunge... I am buying a 35mm RKSport Front Sway Bar off a member on the board... i'll live with the bumpy/stiff ride on bad pavement... I love handling. haha

I am going to contact Sam Strano tomorrow and buy one of his for the rear now. WooT

whonxt?

No, regardless if you buy mine. It is a good choice from experience. I bought the 25mm rear, and the 35mm front, it makes a lot of difference. you can hit corners very hard with little surprises. If you are not looking to drag your car all out, the 35mm is the way to go for street.

stereomandan

I wouldn't go larger than 21mm (1LE size) in the rear, if you have the 35mm bar. I have the 35mm solid front, and the 21mm solid in the rear. Incredible handling difference, and the ride quality didn't get much harsher at all. The handling trade-off is WAY, WAY worth the tiny incease in harshness.

I've weighed my solid front bar, and I'll try to find the post where I listed it's weight.

Dan

Sam Strano

A 35 is not overkill for the street. A 25 rear bar is IMO too much for not only street cars, but road race and autox cars as well. That's why I built the hollow 22. 21-ish is a great size and a terrific match for a 35 front. My rear works like a 21 because I use a thinner wall tubing back there than in the front bar.

And for the record... RK Sport bars are ST bars.

A few words of caution, just to make you think about it and make sure you get the right thing. Consider the weight difference, which is about 14-15 pounds. Consider the fact you get all brand-new hardware and bushings with a new bar. Consider shipping costs as an ST bar packed in the smallest possible box is still 45 pounds with hardware and box included and if it's in the original box that's too big it goes UPS oversize 2, which is the 70 shipping rate. My bar is 21 pounds and ships at a normal oversize rate (I use a smaller box) of 30 pounds.

With a hollow 35 front you add about 2-4 pounds to the car depending on the bar you had on before, if it was a GM bar. If you have a solid bar of some type you save at least 10 pounds and usually more.

BTW, an ST front bar... just the bar is 27 pounds. My bar in a box, with all the hardware, an invoice, etc, is 21 (just weighted it). The bar alone is about 14 pounds.